The Methodology and Data Management Core is critically important to the success of this MAMDC and its EEHSR Component in particular. The centralized availability of expertise in database and study form construction; data entry, monitoring, and retrieval, and the various analytic techniques used to test hypotheses and control for potential confounders are essential resources for all investigators. The Core has assisted educators, epidemiologists, and health services researchers from several divisions and departments in studying a wide variety of disease and demographic groups including systemic lupus erythematosus, osteoarthritis, juvenile dermatomyositis (JDMS), rheumatoid arthritis, and the elderly. Core resources have been used efficiently because of the economies of scale in addition to excellent coordination with the EEHSR component. Recognizing that newer analytic techniques have become available and more accepted and that this proposal represents an expansion of our work in clinical epidemiology and health services research, this proposed Core is both larger to support a greater volume of work and broader t utilize these new analytic techniques. As a result of the Executive Committee's decision to emphasize longitudinal and cost-effectiveness research, experts in advanced statistical techniques (generalized estimating equation (GEE), classification and regression trees (CART), econometric approaches to controlling selection bias, meta-analysis), economics, and decision analysis (stochastic tree modeling, continuous- risk utility assessment) have been recruited as Core co-investigators. Clinical Epidemiology has also been formally included within the Core structure. The Core will support the four EEHSR proposals in this grant application and the funded activities of the JDMS registry and Children's Memorial Hospital. It will continue to contribute to the MAMDC research environment by providing data management and methodologic assistance to investigators who engage in arthritis related research. The institution of a EEHSR/Core research conference and enhanced viability and support for health services research on Northwestern University's Chicago Campus will further heighten the Core's influence on the environment.